BACKGROUND/OBJECTIVE: Children born during England's COVID-19 lockdowns experienced markedly limited social exposure during a crucial developmental window. Given the importance of early interactions in shaping language, executive function and motor skills, this observational cross-sectional study examined developmental outcomes at age 4. METHODS: 205 children born in lockdown were assessed using standardised measures with published prepandemic norms: expressive vocabulary, expressive language and receptive language (Expressive Vocabulary, Word Structure and Sentence Structure subtests of the Clinical Evaluation of Language Fundamentals Preschool-second UK edition); receptive vocabulary (British Picture Vocabulary Scale, third edition); executive function (Global Executive Composite (GEC) and Emergent Metacognition Index (EMI) subscales of the Behaviour Rating Inventory of Executive Function-Preschool); motor skills (Motor Skills subscale from the Vineland Adaptive Behaviour Scales) and non-verbal reasoning (Matrices subtest from the British Ability Scales-3). Analyses (n=189-205) compared scores against prepandemic normative expectations and a within-sample benchmark of non-verbal reasoning to assess strengths and weaknesses against general cognitive development. RESULTS: Compared with normative expectations, Sentence Structure (d=0.59), Expressive Vocabulary (d=0.24), receptive vocabulary (d=0.47) and Matrices (d=0.42) were significantly higher than expected for age. Caregiver-reported executive function was notably lower (GEC, d=-0.46; EMI, d=-0.36), while Word Structure (d=0.01) and Motor Skills (d=0.09) showed no differences. Benchmarked against non-verbal reasoning, Word Structure (d=-0.35), Expressive Vocabulary (d=-0.22), executive function (GEC, d=-0.72; EMI, d=-0.63) and Motor Skills (d=-0.33) were lower than cognitive potential. Sentence Structure (d=0.08) and receptive vocabulary (d=-0.01) were consistent with non-verbal reasoning. CONCLUSIONS: Caregiver-reported executive function was the most noteworthy area of concern for children born in lockdown. Expressive language and motor skills were lower than a benchmark of non-verbal reasoning, suggesting some impacts in relation to cognitive potential. This may lead to educational vulnerabilities and additional support needs in classrooms. Overall, these findings offer valuable early insight into postpandemic developmental impacts and underscore the urgent need for responsive educational policy and targeted support for those now in schooling.